Spin-assisted photoluminescence of polycrystalline α-MnSe

We have studied photoluminescence of α-MnSe in the antiferromagnetic and paramagnetic phases. Two broad, possibly multi-component emission bands centred at about 1.53 and 1.66 eV are observed at 20 K. The frequencies and intensities of these bands show step-like shift in the vicinity of T_N. On the basis of difference in peak energies at T=1.8 K and T_N the d-p-d superexchange interaction in excited state is estimated to be J_2g(exc)=0.918 meV.     

Towards sustainable micro-pollutants’ removal from wastewaters: caffeine solubility,self-diffusion and adsorption studies from aqueous solutions into hydrochars

ABSTRACT

Hydrochars obtained via hydrothermal carbonisation of pistachio shells are both a sustainable and an efficient alternative to commercial activated carbons for the removal of micro-pollutants from wastewaters that are difficult to handle by conventional treatments. Here a combined experimental and molecular simulation approach is adopted for the study of the caffeine/hydrochars aqueous systems. This case study serves to tune a general framework for the rational customisation of surface functional groups on hydrochars for the selective adsorption of micro-pollutants from wastewaters. Caffeine’s solubility, self-diffusion and adsorption results from aqueous solutions at relevant conditions are presented. Insights about the role of surface functional groups over the caffeine adsorption mechanism into hydrochars are gained and discussed.     

Vector boson decays of the Higgs boson

We derive the width of the Higgs boson into vector bosons. General formulas are derived both for the on–shell decay as well for the off–shell decays, and , where . For the off-shell decays the width of the decaying vector boson is properly included. The formulas are valid both for the Standard Model as well as for arbitrary extensions. As an example we study in detail the gauge-invariant effective Lagrangian models where we can have sizable enhancements over the Standard Model that could be observed at LEP. Received: 31 July 1998 / Revised version: 23 September 1998 / Published online: 6 November 1998